Marijuana smoke not as harmful as cigarette smoke, study finds

Marijuana was made illegal as a public health safety measure, but according to results from a new study from the University of Alabama at Birmingham, marijuana smoke is not as damaging to the lungs as cigarette smoke.

Published in the January edition of Journal of the American Medical Association, researchers compared the lung function of marijuana and tobacco users over a 20- year time span. The results showed that tobacco smoke had the same effect on its users as past studies, which is loss of air flow and lung volumes, but the same did not hold true for marijuana smokers.

“At levels of marijuana exposure commonly seen in American, occasional marijuana use was associated with increases in lung air flow fates and increases in lung capacity,” said Dr. Stefan Kertesz, associate professor at University of Alabama at Birmingham, and lead author of the study.

“Those increases were not large, but they were statistically significant. And the data showed that even up to moderately high use levels, one joint a day for seven years, there is no evidence of decreased air-flow rates or lung volumes,” he said.

Medical marijuana has been made legal in 16 states and Washington D.C., and historically has been used to manage such illnesses as AIDS, glaucoma and cancer.

With over 16.7 million people using marijuana monthly, according to the National Survey on Drug Use, these new study findings will allow users to better differentiate and understand how their lungs are affected by marijuana smoke.

“With marijuana use increasing and large numbers of people who have been and continue to be exposed, knowing whether it causes lasting damage to lung function is important for public-health messaging and medical use of marijuana,” he said.

Kertesz also cautions marijuana smokers that this information does not confirm that smoking marijuana is good for the lungs, and these new findings may not apply to heavy users.

“The relationship changes for people who get to high levels of lifetime exposure,” Kertesz said. “At that point, the data suggests there is a decline in lung air-flow rate. There also may be other damaging effects that don’t manifest until extremely high levels of exposure; we did not have enough very heavy marijuana smokers in this study to determine this,” he explained.

Lastly, the researchers were careful to mention that the scope of this study was only to determine the relationship between marijuana smoking and proper lung function, and did not study the affects on other parts of the body. They also maintain that the researchers do not condone the use of marijuana.

“Marijuana is still an illegal drug, and it has many complicated effects on the human body and its function,” Kertesz said.